Peak Off-Scale
Posted: Wed Aug 22, 2007 7:06 pm
I injected 0.1mg/ml (20ul) of my drug substance on the HPLC system and I get a nice symmetrical peak but I inject it on another HPLC system and the peak is off scale. Why?
Without details such as instrument types/models and operating settings, we can only make some assumptions and provide general ideas/guesses.
Just considering the detector, here are a few things that you can compare: cell path lengths, time constant settings, age of the lamps, and range settings. There are others.
A longer cell path length can give a larger signal (taller peak or larger peak area).
A smaller time constant will give a larger signal.
A newer lamp has more energy and can give a larger peak signal.
Some detectors have range settings that allow for scaling the peak larger (or smaller).
Please give more details about your two instruments. Also, compare the operating settings between the two systems and let us know about any differences. Then we can give you a more exact reason for the differences in peak heights.
Regards,
Dan